Problem: `fatal: too-short tree object` when executing hash-object on tree

Problem: I'm trying to reproduce the identifier of a tree object using `git cat-file -p <tree object identifier> | git hash-object -t tree --stdin`

This results in an error: `fatal: too-short tree object`

To replicate: `git cat-file -p HEAD` `git cat-file -p <tree object identifier from output of above> | git hash-object -t tree --stdin`

This works for other object types but not trees. What am I doing wrong?